Oxides and Insulators

Figure:a) Large scale RT ncAFM image of molecules on the NiO surface.
b) Second pass frequency shift image on a single molecule. c) Suggested model for the molecule adsorption.

We performed high-resolution topographic measurements using bimodal nc-AFM at room temperature of the anchoring part of a larger
dye molecule (DCPDMbpy) adsorbed on a NiO(001) crystal surface. First, the surface structure of NiO(001) is resolved with atomic
resolution. Second, by using the multipass technique, we study the adsorption of molecule. For isolated molecule, small cluster
and larger island we found that molecules are lying flat on the surface. Enantiomeric adsorption at room temperature is also
evidenced.

We used a Low Temperature Plasma (LTP) source
to create defects on the clean KBr(001) surface and characterized the surface at the atomic scale using our
home made room temperature ncAFM system .
Depending on the gas used to create the plasma we can obtain various nanostructuration of the surface.
With Argon, we observed nanoclusters creation presenting edges alignment along unfavourable polar step edge.
With Helium, we are able to create well distributed single atomic vacancies stable at room temperature.

C60 islands reshaping on BNL surface via ncAFM

Figure:Tip-Induced Shape Modi cation of a C60 Island.
a-b) Topographic images recorded before and after the tip-induced shape modi cation process.
c) Profiles of the C60 island acquired while modifying its shape from triangular to hexagonal.
d-h) Sequence showing the shape modi cation process. The tip was continuously scanned over the island but the tip/sample distance was intentionally varied by changing frequency shift.

We used our home made RT AFM microscope
, to study C60 molecules deposited on an organaic layered crystal (BNL). C60 molecules form islands at room temperature on the surface.
We demonstrate the dynamical reshaping of those C60 nano-structures under the local action of the AFM tip at room temperature.
The dissipated energy is about 75 meV and can be interpreted as the activation energy required for this migration process.

Electrospray Deposition of organic molecules on bulk insulators

We used a modified commercial
electrospray deposition device , connected to the vacuum chamber of our
microscope, to introduce large organic
molecules in UHV and deposited them on bulk insulator surfaces. At large coverage, we measure a charging of the surface. Annealing is necessary
to reduce the charging and observe molecular islands on the surface. At low coverage, no charging effect is measured and isolated single molecules
are observed.

We demonstrated the investigation of different Cu-TCPP binding geometries and adsorption sites on rutile TiO2(110) at room temperature using nc-AFM at the second flexural resonance of the cantilever and FM-KPFM.
Topography images revealed two configurations that were differently oriented with respect to the TiO2 surface structure. KPFM indicated that there is a charge transfer to the surface upon adsorption leading to an interfacial
dipole moment. The experimental results were verified and further investigated with DFT calculations.

Atomic manipulation on bulk insulator at room temperature with ncAFM.

Vertical manipulation was successfully performed several times, perfectly aligning 20 Br- ions in the NaCl surface,
forming a "Swiss cross" with a size of 5,64 x 5,64 nm. Note that this is the largest number of the atomic manipulations
ever achieved at Room Temperature. The Br- ions are positioned at every other Cl- ion site on the surface, and the fabricated
cross is stable for a relatively long time.

Atomically resolved bimodal DFM images of a KBr(001).

Figure: Atomically resolved bimodal DFM images of a KBr(001) surface obtained at a series of quasi-constant heights.

We present bimodal dynamic mode atomic force microscopy, in which two resonance modes are excited
and detected. The combination of subangstrom amplitude at the second flexural resonance of a commercially available silicon cantilever with
the commonly-used large amplitude oscillation at the fundamental resonance improves the spatial resolution while avoiding jump-to-contact
instabilities.